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Saturday, June 1, 2013

computer communication and networks CCN International Islamic University Islamabad (IIUI)





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Chapter 1
The correct answer for each question is indicated by a This is the correct answer..

1
CORRECT
In a _______ connection, more than two devices can share a single link.

A)
Point-to-point

B)
Primary
This is the correct answer.
C)
Multipoint

D)
Secondary


2
CORRECT
Communication between a computer and a keyboard involves ______________ transmission.

A)
Full-duplex

B)
Half-duplex
This is the correct answer.
C)
Simplex

D)
Automatic


3
CORRECT
In a network with 25 computers, which topology would require the most extensive cabling?

A)
Star
This is the correct answer.
B)
Mesh

C)
Bus

D)
Ring


4
CORRECT
Which topology requires a central controller or hub?
This is the correct answer.
A)
Star

B)
Mesh

C)
Bus

D)
Ring


5
INCORRECT
The _______ is the physical path over which a message travels.

A)
Protocol
This is the correct answer.
B)
Medium

C)
Signal

D)
All the above


6
INCORRECT
Which organization has authority over interstate and international commerce in the communications field?

A)
ITU-T

B)
IEEE

C)
ISO
This is the correct answer.
D)
FCC


7
CORRECT
The information to be communicated in a data communications system is the _______.

A)
Medium

B)
Protocol

C)
Transmission
This is the correct answer.
D)
Message


8
INCORRECT
Frequency of failure and network recovery time after a failure are measures of the _______ of a network.

A)
Performance

B)
Security
This is the correct answer.
C)
Reliability

D)
Feasibility


9
CORRECT
In _______ transmission, the channel capacity is shared by both communicating devices at all times.
This is the correct answer.
A)
Full-duplex

B)
Simplex

C)
Half-duplex

D)
Half-simplex


10
CORRECT
An unauthorized user is a network _______ issue.

A)
Performance

B)
Reliability
This is the correct answer.
C)
Security

D)
All the above


11
INCORRECT
Which topology requires a multipoint connection?

A)
Mesh

B)
Star

C)
Ring
This is the correct answer.
D)
Bus


12
CORRECT
A television broadcast is an example of _______ transmission.

A)
Half-duplex

B)
Full-duplex
This is the correct answer.
C)
Simplex

D)
Automatic


13
CORRECT
A _______ connection provides a dedicated link between two devices.

A)
Multipoint
This is the correct answer.
B)
Point-to-point

C)
Primary

D)
Secondary


14
CORRECT
A cable break in a _______ topology stops all transmission.

A)
Mesh

B)
Star

C)
Primary
This is the correct answer.
D)
Bus

///////////////////////////////////////////////////////////
Chapter 2
The correct answer for each question is indicated by a This is the correct answer..

1
INCORRECT
The _______ layer changes bits into electromagnetic signals.
This is the correct answer.
A)
Physical

B)
Transport

C)
None of the above

D)
Data link


2
CORRECT
The physical layer is concerned with the transmission of _______ over the physical medium.

A)
Programs

B)
Protocols
This is the correct answer.
C)
Bits

D)
Dialogs


3
CORRECT
Mail services are available to network users through the _______ layer.

A)
Data link

B)
Physical
This is the correct answer.
C)
Application

D)
Transport


4
CORRECT
As the data packet moves from the lower to the upper layers, headers are _______.

A)
Added

B)
Rearranged

C)
Modified
This is the correct answer.
D)
Subtracted


5
CORRECT
As the data packet moves from the upper to the lower layers, headers are _______.

A)
Removed
This is the correct answer.
B)
Added

C)
Rearranged

D)
Modified


6
INCORRECT
The _______ layer lies between the network layer and the application layer.

A)
Data link

B)
Physical
This is the correct answer.
C)
Transport

D)
None of the above


7
INCORRECT
Layer 2 lies between the physical layer and the _______ layer.

A)
Data link
This is the correct answer.
B)
Network

C)
Transport

D)
None of the above


8
INCORRECT
When data are transmitted from device A to device B, the header from A's layer 4 is read by B's _______ layer.

A)
Application

B)
Physical
This is the correct answer.
C)
Transport

D)
None of the above


9
INCORRECT
Which layer functions as a liaison between user support layers and network support layers?

A)
Network layer
This is the correct answer.
B)
Transport layer

C)
Physical layer

D)
Application layer


10
CORRECT
What is the main function of the transport layer?
This is the correct answer.
A)
Process-to-process delivery

B)
Node-to-node delivery

C)
Synchronization

D)
Updating and maintenance of routing tables


11
CORRECT
Which of the following is an application layer service?

A)
Remote log-in

B)
File transfer and access

C)
Mail service
This is the correct answer.
D)
All the above


12
INCORRECT
The Internet model consists of _______ layers.

A)
Three
This is the correct answer.
B)
Five

C)
Seven

D)
Eight


13
CORRECT
The process-to-process delivery of the entire message is the responsibility of the _______ layer.

A)
Physical

B)
Network
This is the correct answer.
C)
Transport

D)
Application


14
CORRECT
The _______ layer is the layer closest to the transmission medium.

A)
Network
This is the correct answer.
B)
Physical

C)
Data link

D)
Transport


///////////////////////////////////////////////////////////
Chapter 7
The correct answer for each question is indicated by a This is the correct answer..

1
INCORRECT
The VLF and LF bands use _______ propagation for communications.

A)
Space
This is the correct answer.
B)
Ground

C)
Sky

D)
Line of sight


2
CORRECT
Category 1 UTP cable is most often used in _______ networks.

A)
Infrared
This is the correct answer.
B)
Telephone

C)
Fast Ethernet

D)
Traditional Ethernet


3
CORRECT
BNC connectors are used by _______ cables.

A)
Fiber-optic

B)
UTP

C)
STP
This is the correct answer.
D)
Coaxial


4
CORRECT
Which of the following is not a guided medium?

A)
Twisted-pair cable

B)
Fiber-optic cable
This is the correct answer.
C)
Atmosphere

D)
Coaxial cable


5
CORRECT
In an environment with many high-voltage devices, the best transmission medium would be _________.

A)
Twisted-pair cable

B)
Coaxial cable

C)
The atmosphere
This is the correct answer.
D)
Optical fiber


6
CORRECT
_______ cable consists of an inner copper core and a second conducting outer sheath.
This is the correct answer.
A)
Coaxial

B)
Twisted-pair

C)
Fiber-optic

D)
Shielded twisted-pair


7
CORRECT
In fiber optics, the signal source is _______ waves.

A)
Very low-frequency
This is the correct answer.
B)
Light

C)
Radio

D)
Infrared


8
CORRECT
Smoke signals are an example of communication through _______.

A)
A guided medium

B)
A refractive medium
This is the correct answer.
C)
An unguided medium

D)
A small or large medium


9
CORRECT
Which of the following primarily uses guided media?

A)
Cellular telephone system

B)
Satellite communications
This is the correct answer.
C)
Local telephone system

D)
Radio broadcasting


10
INCORRECT
What is the major factor that makes coaxial cable less susceptible to noise than twisted-pair cable?
This is the correct answer.
A)
Outer conductor

B)
Inner conductor

C)
Diameter of cable

D)
Insulating material


11
INCORRECT
The RG number gives us information about _______.

A)
Optical fibers

B)
Twisted pairs
This is the correct answer.
C)
Coaxial cables

D)
All the above


12
CORRECT
Transmission media are usually categorized as _______.
This is the correct answer.
A)
Guided or unguided

B)
Fixed or unfixed

C)
Determinate or indeterminate

D)
Metallic or nonmetallic


13
INCORRECT
The _______ is an association that sponsors the use of infrared waves.

A)
EIA
This is the correct answer.
B)
IrDA

C)
FCC

D)
PUD


14
CORRECT
In an optical fiber, the inner core is _______ the cladding.

A)
Less dense than
This is the correct answer.
B)
Denser than

C)
The same density as

D)
Another name for


15
INCORRECT
The inner core of an optical fiber is _______ in composition.

A)
Copper

B)
Bimetallic
This is the correct answer.
C)
Glass or plastic

D)
Liquid


16
CORRECT
When a beam of light travels through media of two different densities, if the angle of incidence is greater than the critical angle, _______ occurs.

A)
Refraction
This is the correct answer.
B)
Reflection

C)
Incidence

D)
Criticism


17
CORRECT
In _______ propagation, the beam of propagated light is almost horizontal, and the low-density core has a small diameter compared to the cores of the other propagation modes.
This is the correct answer.
A)
Single-mode

B)
Multimode step-index

C)
Multimode graded-index

D)
Multimode single-index


18
CORRECT
_______ is the propagation method subject to the greatest distortion.

A)
Single-mode
This is the correct answer.
B)
Multimode step-index

C)
Multimode graded-index

D)
Multimode single-index


19
CORRECT
In _______ propagation, the core is of varying densities.

A)
Single-mode

B)
Multimode step-index
This is the correct answer.
C)
Multimode graded-index

D)
Multimode single-index


20
INCORRECT
When we talk about unguided media, usually we are referring to _______.

A)
Metallic wires

B)
Nonmetallic wires
This is the correct answer.
C)
The air

D)
None of the above


21
CORRECT
Transmission media are closest to the _______ layer.

A)
Application
This is the correct answer.
B)
Physical

C)
Network

D)
Transport


22
CORRECT
Radio wave and microwave frequencies range from _______.

A)
3 to 300 KHz

B)
300 KHz to 3 GHz
This is the correct answer.
C)
3 KHz to 300 GHz

D)
3 KHz to 3000 GHz


23
CORRECT
Optical fibers, unlike wire media, are highly resistant to _______.

A)
High-frequency transmission

B)
Low-frequency transmission

C)
Refraction
This is the correct answer.
D)
Electromagnetic interference


24
CORRECT
In _______ propagation, low-frequency radio waves hug the earth.

A)
Space
This is the correct answer.
B)
Ground

C)
Sky

D)
Line of sight


25
CORRECT
When the angle of incidence is _______ the critical angle, the light beam bends along the interface.

A)
More than

B)
Less than
This is the correct answer.
C)
Equal to

D)
None of the above


26
INCORRECT
A parabolic dish antenna is a(n) _______ antenna.

A)
Omnidirectional

B)
Bidirectional

C)
Horn
This is the correct answer.
D)
Unidirectional


/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
Chapter 19
                

On a network that uses NAT, the _______ has a translation table.

 
This is the correct answer.
A)
Router

B)
Switch

C)
Server

D)
None of the above


2
INCORRECT
Identify the class of IP address 229.1.2.3.

A)
Class A

B)
Class B

C)
Class C
This is the correct answer.
D)
Class D


3
INCORRECT
On a network that uses NAT, _______ initiates the communication.
This is the correct answer.
A)
An internal host

B)
An external host

C)
The router

D)
(a) or (b)


4
CORRECT
A subnet mask in class B can have _______ 1s with the remaining bits 0s.

A)
Nine
This is the correct answer.
B)
Seventeen

C)
Three

D)
Fourteen


5
INCORRECT
A subnet mask in class C can have _______ 1s with the remaining bits 0s.
This is the correct answer.
A)
Twenty-five

B)
Twelve

C)
Seven

D)
Ten


6
CORRECT
Identify the class of IP address 4.5.6.7.
This is the correct answer.
A)
Class A

B)
Class B

C)
Class C

D)
Class D


7
CORRECT
Identify the class of IP address 191.1.2.3.

A)
Class A
This is the correct answer.
B)
Class B

C)
Class C

D)
Class D


8
INCORRECT
A subnet mask in class A can have _______ 1s with the remaining bits 0s.
This is the correct answer.
A)
Nine

B)
Four

C)
Thirty-three

D)
Three


9
INCORRECT
Class _______ has the greatest number of hosts per given network address.
This is the correct answer.
A)
A

B)
B

C)
C

D)
D


10
INCORRECT
A subnet mask in class B has nineteen 1s. How many subnets does it define?

A)
128
This is the correct answer.
B)
8

C)
32

D)
64


11
INCORRECT
In _______ routing, the full IP address of a destination is given in the routing table.

A)
Next-hop
This is the correct answer.
B)
Host-specific

C)
Network-specific

D)
Default


12
CORRECT
A subnet mask in class C has twenty-five 1s. How many subnets does it define?

A)
0
This is the correct answer.
B)
2

C)
8

D)
16


13
INCORRECT
Given the IP address 180.25.21.172 and the subnet mask 255.255.192.0, what is the subnet address?

A)
180.25.21.0

B)
180.25.8.0
This is the correct answer.
C)
180.25.0.0

D)
180.0.0.0


14
INCORRECT
Given the IP address 18.250.31.14 and the subnet mask 255.240.0.0, what is the subnet address?

A)
18.9.0.14

B)
18.0.0.14

C)
18.31.0.14
This is the correct answer.
D)
18.240.0.0


15
INCORRECT
_______ is a client-server program that provides an IP address, subnet mask, IP address of a router, and IP address of a name server to a computer.

A)
NAT
This is the correct answer.
B)
DHCP

C)
CIDR

D)
ISP


16
INCORRECT
In _______, each packet of a message need not follow the same path from sender to receiver.

A)
The virtual approach to packet switching
This is the correct answer.
B)
The datagram approach to packet switching

C)
Message switching

D)
None of the above


17
CORRECT
An IP address consists of _______ bits.

A)
8
This is the correct answer.
B)
32

C)
4

D)
Any of the above


18
INCORRECT
On a network that uses NAT, the router can use _______ global address(es).
This is the correct answer.
A)
A pool of

B)
One

C)
Two

D)
None of the above


19
CORRECT
In _______ routing, the mask and destination addresses are both 0.0.0.0 in the routing table.
This is the correct answer.
A)
Default

B)
Next-hop

C)
Network-specific

D)
Host-specific


20
INCORRECT
A subnet mask in class A has fourteen 1s. How many subnets does it define?
This is the correct answer.
A)
64

B)
128

C)
32

D)
8


21
CORRECT
In which type of switching do all the packets of a message follow the same channels of a path?
This is the correct answer.
A)
Virtual circuit packet switching

B)
Message switching

C)
Datagram packet switching

D)
None of the above


22
INCORRECT
In _______ routing, the destination address is a network address in the routing table.
This is the correct answer.
A)
Network-specific

B)
Host-specific

C)
Next-hop

D)
Default


23
INCORRECT
Given the IP address 201.14.78.65 and the subnet mask 255.255.255.224, what is the subnet address?
This is the correct answer.
A)
201.14.78.64

B)
201.14.78.32

C)
201.14.78.65

D)
201.14.78.12

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